tag_utils: Comment that case should not happen.

diff --git a/todo_tag_utils.ml b/todo_tag_utils.ml
index 29a760b..b2990a8 100644 (file)
--- a/todo_tag_utils.ml
+++ b/todo_tag_utils.ml
@@ -15,6 +15,8 @@ let string_of_tag name colour =
     (* black fg *)
     | "cyan"   -> 46, 30
     | "yellow" -> 43, 30
+
+    (* Should never happen because of database constraints. *)
     | _ -> assert false in
 
   sprintf "\x1b[%d;%dm\x1b[%d;%dm %s \x1b[0m" 1 fg 1 bg name